Nuclear reactions, symbols

The meaning of the symbolic expression indicating a nuclear reaction ... 

A further group of elements, the transuranium elements, has been synthesized by artificial nuclear reactions in the period from 1940 onwards their relation to the periodic table is discussed fully in Chapter 31 and need not be repeated here. Perhaps even more striking today are the predictions, as yet unverified, for the properties of the currently non-existent superheavy elements.Elements up to lawrencium (Z = 103) are actinides (5f) and the 6d transition series starts with element 104. So far only elements 104-112 have been synthesized, ) and, because there is as yet no agreement on trivial names for some of these elements (see pp. 1280-1), they are here referred to by their atomic numbers. A systematic naming scheme was approved by lUPAC in 1977 but is not widely used by researchers in the field. It involves the use of three-letter symbols derived directly from the atomic number by using the... 

Plutonium (symbol Pu atomic number 93) is not a naturally occurring element. Plutonium is formed in a nuclear reaction from a fertile U-238 atom. Since U-238 is not fissile, it has a tendency to absorb a neutron in a reactor, rather than split apart into smaller fragments. By absorbing the extra neutron, U-238 becomes U-239. Uranium-239 is not very stable, and undergoes spontaneous radioactive decay to produce Pu-239. 

The "ordinary chemical reactions" discussed to this point involve changes in the outer electronic structures of atoms or molecules. In contrast nuclear reactions result from changes taking place within atomic nuclei. You will recall (Chapter 2) that atomic nuclei are represented by symbols such as... 

To summarize, the equation for a nuclear reaction is balanced when the total charge and total mass number of the products equals the total charge and total mass number of the reactants. This conservation requirement is one reason why the symbol for any nuclide includes its charge number (Z) as a subscript and its mass number as a superscript. These features provide a convenient way to keep track of charge and mass balances. Notice that in the equation for neutron decay, the sum of the subscripts for reactants equals the sum of the subscripts for products. Likewise, the sum of the superscripts for reactants equals the sum of the superscripts for products. We demonstrate how to balance equations for other reactions as they are introduced. 

Most nuclear reactions involve the breaking apart of the nucleus into two or more different elements or subatomic particles. If we know all but one of the particles, then the unknown particle can be determined by balancing the nuclear equation. When chemical equations are balanced, we add coefficients to ensure that there are the same number of each type of atom on both the left and right of the reaction arrow. However, in order to balance nuclear equations we ensure that there is the same sum of both mass numbers and atomic numbers on the left and right of the reaction arrow. Recall that we can represent a specific isotope of an element by the following symbolization ... 

A is the mass number (sum of protons and neutrons), Z is the atomic number (number of protons), and X is the element symbol (from the periodic table). In balancing nuclear reactions, ensure that the sum of all A values on the left of the reaction arrow equals the sum of all A values to the right of the arrow. The same will be true of the sums of the atomic numbers, Z. Knowing that these sums have to be equal allows you to predict the mass and atomic number of an unknown particle, if we know all the others. 

When balancing nuclear reactions, be sure you use the atomic number of the unknown and not the mass number to determine the element symbol. 

Americium - the atomic number is 95 and the chemical symbol is Am. The name derives from America where it was first synthesized in a series of successive neutron capture reactions in the element plutonium, Pu, in a nuclear reactor in 1944 by American scientists under Glenn T. Seaborg at the University of California lab in Berkeley, California, using the nuclear reaction Pu ( n, y) Y) P Am. Americium is the sixth element in the Actinide... 

Dubnium - the atomic number is 105 and the chemical symbol is Db. The name derives from the location of the Russian research center, the Joint Institute for Nuclear Research lab in Dubna , Russia. The first synthesis of this element is jointly credited to the American scientific team at the University of California in Berkeley, California imder Albert Ghiorso and the Russian scientific team at the JINR (Joint Institute for Nuclear Reactions) lab in Dubna, Russia, imder Georgi N. Flerov in 1970. The longest half-life associated with this unstable element is 34 second Db. 

Hassium - the atomic number is 108 and the chemical symbol is Hs. The name derives from the Latin Hassia for the German state of Hesse , whose former capital was Darmstadt. The element was first synthesized by German physicists at the GSI (Center for Heavy-Ion Research) Lab at Darmstadt, Germany in 1984 using the nuclear reaction ° Pb ( Fe, n) Hs. The longest half-life associated with this unstable element is 11 minute Hs. 

Neptunium - the atomic niunber is 93 and the chemical symbol is Np. The name derives from the planet Neptune (the Roman god of the sea), since it is the next outer-most planet beyond the planet uranus in the solar system and this element is the next one beyond uranium in the periodic table.lt was first synthesized by Edwin M. McMillan and Philip H. Abelson in 1940 via the nuclear reaction n, y) U P = p. The longest half-life associated with this mistable... 

Plutonium - the atomic number is. 94 and the chemical symbol is Pu. The name derives from the planet Pluto, (the Roman god of the underworld). Pluto was selected because it is the next planet in the solar system beyond the planet Neptime and the element plutonium is the next element in the period table beyond neptunium. Plutonium was first synthesized in 1940 by American chemists Glenn T. Seaborg, Edwin M. McMillan, Joseph W. Kennedy and Arthur C. Wahl in the nuclear reaction U( H, 2n) Np = P => Pu. The longest half-life associated with this unstable element is 80 million year Pu. 

Conservation of mass and charge are used when writing nuclear reactions. For example, let s consider what happens when uranium-238 undergoes alpha decay. Uranium-238 has 92 protons and 146 neutrons and is symbolized as After it emits an alpha particle, the nucleus now has a mass number of 234 and an atomic number of 90. 

The first symbol represents deuterium. The number 1 below the line is the number of protons. The number 2 above the line shows the mass of the isotope. The other reactant is tritium. When the nuclei fuse, there are now two protons. The only element that has two protons is helium. Since the number of protons and the masses on both sides of nuclear reactions must be equal, that leaves one subatomic particle with a mass of 1 amu and no charge—a neutron. 

A shorthand notation has been developed for nuclear reactions such as the reaction discovered by Curie and Joliot. The parent (or target) nuclide and the daughter nuclide are separated by parentheses that contain the symbols for the particle that hits the target and the particle or particles released in this reaction. 

Hydrogen-2 is called deuterium and is often represented by the symbol D. Hydrogen-3 is known as tritium and is often represented by the symbol T. Nuclear reactions between very light atoms similar to the reaction above are the energy source behind the sun and the hydrogen bomb. 

Quantities and Units-Part 9 Atomic and Nuclear Physics Quantities and Units-Part 10 Nuclear Reactions and Ionizing Radiations Quantities and Units-Part 11 Mathematical Signs and Symbols for... 

When it is desired to distinguish betw een isotopes, the approximate atomic mass is given as a superscript to the symbol thus is light hydrogen and is heavy hydrogen (deuterium). Oxygen consists mainly of with much smaller amounts of and When ec]ua-tions for nuclear reactions are written the atomic number is also often placed as a left subscript, thus ... 

Nuclear reactions are usually represented as eqs. (4.1) and (4.2), that is, on the left is the symbol for the target nuclides, the first symbol in the parenthesis indicates the bombarding particle (or projectile), the second the emitted particles, and the symbol of the product on the right. In the equation, the left side of the comma shows the system of the reactants, and the right the system of the products. Before and after the nuclear reaction, both the sum of mass number and the sum of atomic number remain unchanged. 

In order to discuss nuclear reactions in any depth, we need to understand how to write and balance the equations. Writing a nuclear equation differs somewhat from writing equations for chemical reactions. In addition to writing the symbols for various chemical elements, we must also explicitly indicate protons, neutrons, and electrons. In fact, we must show the numbers of protons and neutrons present in every species in such an equation. 

Beta particles (symbolized (3, (3 , or more usually °(3) are negatively charged particles identified as high-speed electrons. (The emission of electrons from the nucleus may seem strange, but as you ll see shortly, (3 particles arise as a result of a nuclear reaction.)... 

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